Combined fluid-cooled vacuum tube and cooling block



Feb. 7, 1939. C. w. 'HANSELL 2,146,541

COMBINED FLUID-COOLEDy VACUUM TUBE AND COOLING BLOCK CLARENCE W. HANSELLBY g b;

ATTORN EY Feb. 7, 1939.r c. w. HANSELL. 2,146,541

l COMBINED FLUID'COOLED VACUUM TUBE AND COOLING BLOCK Filed July 50,1936 6 Sheets-Sheet 2 lNVENTOR CLARENCE W. HANSELL MWL-gw ATTORNEY Feb.7, 1939. c. w. HANSELL l 2,146,541

COMBINED FLUID-COOLED VACUUMVTUBE AND COOLING BLOCK Filed July so, 195ee sheets-sheet s o O Ol f 8 g o INVENTOR CLARENC? HANSELL ATTORNEY Feb.7, 1939. c. w. l-lANsELL 2,146,541v

COMBINED FLUID-COOLED VACUUM TUBE AND COOLING BLOCK Filed July 30, 19566 Sheets-Sheet 4 CATHODE HEAT/NG SUPPLY 4C Fr- 37 l fl 56 MGH FREa//f/vcY /Npur T 34K' 35' CAN/005 I 420J HEAT/NG SUPPLY /f/GH FREQUENCY 00m/7'our/0r I E@ 4d cfm/00E -I- T oz/rz/r HMM/65u Y WC/ TUBE @2 700 E f 12g-7702 .1 g C4 704 lNvENToR 7V. g//vPz/ CLARENCE w.HANsELL O 7/2 -BY l g705 /l/(fV-M/ 3 c, @3 ATTORNEY Feb. 7, 1939. C, W, HANSELL 2,146,541

COMBINED FLUID-COOLED VACUM TUBE AND COOLING BLOCK Filed July 30, 1956 6Sheets-Sheet 5 NVENTOR CLARENCE ANsELL BY Aww/V ATTORNEY Feb. 7, 1939.c. w. HANSELL' COMBINED FLUID-COOLED VACUUM TUBE AND COOLING BLOCK FiledJuly 50, 1936 6 Sheets-Sheet 6 INVENTOR. HARENC/E HANSEL A TTORN E Y.

Patented Feb. 7, 1939 UNITED STATES COMBINED FLUID-COOLED VACUUM TUBEAND COOLING BLOCK Clarence W. Hansell, Port Jefferson, N. Y., assignorto Radio Corporation of America, a corporation of Delaware ApplicationJuly 30, 1936, Serial No. 93,393

12 -Claims.

This invention relates to an improved means for cooling the anodes ofliquid cooled vacuum tubes and to a combined fluid cooled radiotransmission tube and cooling block which is particularly adapted foruse in a short wave transmitting circuit or for amplifiers andmodulators which require relatively high power dissipation.

In the prior art7 the anode surface of the radio transmission tube wasusually surrounded by a body of cooling fluid such as water or oilcontained in a reservoir having inlet and outlet pipes to supply thecirculating cooling fluid. Frequently, when tubes such as the RCA-846and 207 have been operated in short wave circuits, or when tubes such asthe RCA-848 and 207 have been used as audio ampliers or as modulators inthe Heising modulating circuit, the temperature rise in the coolingfluid was such that there was danger of the cooling solution boiling atthe contact surface of the anode. By this invention, an increase in thepermissible power dissipation without danger of boiling at the anodesurface, is obtained.

An object of this invention is to improve fluid cooled transmittingtubes for use in ultra-high frequency circuits or in ampliers,modulators, etc., over those of the prior art.

Another object of this invention is to improve the overall powerconverting ability of fluid cooled electron discharge devices, so thathigher power inputs and higher power outputs can be obtained than waspreviously possible when devices of the prior art were used in shortwave transmitting circuits.

Other objects of this invention are to permit a reduction in the rate ofcooling uid flow to the tubes and/or to permit higher temperatures ofthe fluid supply, thus decreasing the size and cost of the coolingsystems and facilitating the use of radiators for cooling the supplyfluid. Incidentally, the higher temperatures facilitate use of theenergy carried away from the tubes in heating the building in which thetubes are used.

A further object of this invention is to provide means permitting theuse of an anti-freeze cooling solution, which has a tendency to reducethe boiling point of the cooling liquid for a transmitting tube.Heretofore, for example, the use of alcohol in the water to reduce thefreezing temperature has not been feasible because of the high operatingtemperatures required by the cooling liquid adjacent the tube. Thevacuum tubes may be operated in unheated rooms or buildings, bringingabout considerable economies, if the cooling liquid is made safe fromfreezing.

Still other objects of this invention are to provide means for changingfrom one tube to another without opening of the fluid cooling system, aswas previously necessary, and also to provide a combined vacuum tube andneutralizing condenser block arrangement which lends itself to compactand efficient design of high frequency circuits.

Features of this invention reside in the provision of a tapered anodesleeve, corresponding to a tapered aperture in a cooling block, tofacilitate making intimate contact between the sleeve and the block forincreasing the cooling of and heat conduction from the anode, bysecurely maintaining the tapered surfaces in intimate contact with eachother. The increased thickness of metal, provided by addition f thetapered sleeve to the anode, serves to conduct heat away from spots onthe anode where dissipation is relatively high and this, combined withgreater area of contact between metal and cooling liquid, eliminatesboiling in spots, which occurs when tubes are cooled by bringing thecooling liquid into direct contact with the anode.

Another feature is the provision 0f a novel and combined casingarrangement whereby a vacuum tube is located along the side of acompressed air neutralizing condenser of the type disclosed in thecopending joint application of Hansell, Usselman and Latimer, Ser. No.27,678, filed June 21, 1935.

Still another feature of my present invention resides in an arrangementwherein when a tube is installed, the tapered portion of a. vacuum tubeanode is securely drawn into the corresponding taper in a cooling block,so that the surfaces are locked in intimate contact, thus reducingsurface contact resistance to a minimum. The same arrangement serves toforce the tube out of the tapered block when it is desired to remove it.

My present invention will be further described with specific referenceto. the accompanying drawing, in which:

Fig. 1 is a longitudinal section partly in elevation oi the compressedair condenser, vacuum tube and cooling block;

Fig. 2 is a bottom View of Fig. l;

Fig. 3 is a detailed cross-sectional view taken on line 3 3 of Fig. 1,of the combined vacuum tube block;

Figs. 4a, 4b, 4c and 4d are schematic diagrams of three different formsof high frequency circuit in which the indirectly cooled vacuum tube andthe combined tube and condenser of this invention may be used;

Fig. 5 is a perspective View of a spare vacuum tube;

Fig. 6 is a schematic circuit diagram of still another balanced circuitemploying the water structure of my present invention; and

Fig. 7 shows schematically the mechanical arrangement of the coolingparts of the wiring diagram 4d showing particularly the input of thecooling circuit for the system; while Figs. 8, 8a and 8b are perspectiveviews of members I, it and s3, respectively.

Fig. 9 is an elevation of a condenser, vacuum Vtube and cooling block,the tube anode cooling portion being shown in section.

Referring now in detail to Figs. 1, 2 and 3 of the drawings, I indicatesthe combined compressed air condenser and vacuum tube cooling block orcasing of relatively heavy metallic walls of good heat and electricalconductivity, to facilitate rapid heat radiation, such as copper,aluminum or brass. It will be noted that the cross-sectional area of thecasing is greater than the internal aperture lA, the'internal apertureor bore IA being accurately nished and polished so as to provide one ofthe condenser electrode surfaces. The upper portion of the casing I isprovided with a conelike insulator 2 which is composed of a goodinsulating material, such as Isolantite, Steatite, Pyrex, porcelain orany suitable material having the necessary and requisite mechanicalstrength and insulating qualities. The lower end of the insulator 2 isprovided with an enlarged section 2A over which a metallic ring 3securely fastens the insulator to the casing I by suitable screws Toprovide a gas-tight seal and to prevent breakage of the insulator, alead, varnished silk, rubber or other suitable gasket material 5 isemployed between members I, 2 and 3. The member 3 is provided with arounded ridge 3A which acts as a` corona shield to prevent the insulatorfrom arcing over due to the high voltage. Within the central portion ofinsulator 2 a long hollow stem 6 is located, the lower portion beingprovided with threads 'I to secure the guide 8 for securing and guidingthe main portion of the inner electrode 3. The center electrode 9 isarranged to be removable by means of threads and screws 9A so that itmay be interchanged with other electrode members of diiierent lengthsand diameters, so that the capacity of the condenser may be easilychanged, as required, by changing the dielectric space betweenelectrodes I and 9.

A shoulder I il retains stem againstthe shoulder gasket II within theinsulator 2'. The upper portion of stem 6 is threaded with a fine threadl2, by means of which the adjustable lower portion of the centralelectrode is raised or lowered within the aperture IA, with the aid ofand against the internal iluid pressure, by means of adjusting nut i3.'Ihe adjustable portion of the central electrode is maintained in thedesired position by means of the internal uid pressure forcing theadjustable portion of the central electrode assembly up against a rodI5. The upper portion of adjusting nut I3 is arranged to retain a smallhardened steel ballbearing i@ which actuates a metallic rod I5 thatpasses through the stem 6, and terminates in a follower I6 upon which ismounted the adjustable lower portion I? of the inner electrode s. Thelengths of the push rod I5 and stem G is made such` that the downwardmovement of the bellows is limited by the internal shoulder I3A strikingat 6A. This prevents the bellows from being damaged by stretching. Italso limits the reduction of dielectric thickness or uid space at thelower end of the bellows to such an amount that the condenser cannotarc-over or short-circuit. This lower portion Il is likewise arranged tobe easily removable by means of screw I'IA so that it may beinterchanged with other members of diiferent length and diameter. Inorder to provide a sensitive and accurate adjustment of electriccapacity between the inner and outer Yelectrodeaa novel arrange- Theouter casing I, especially that portion to 4 the left of the dot anddash line 4 4, ordinarily acts as the outer electrode and is an integralpart of the transmitting circuit assembly as shown for example by Fig.4a. However, it may be provided with a terminal or lugr2I, the centralelectrode beingV also provided with a terminal lug 22 which is retainedin place by means of nuts 23. The lower nut 23 also acts to retain thestem 6 in place within the insulator by being tightly clamped againstthe Washer 2li and the washer or gasket 25.

The casing I is provided with an air valve 2 anda cap 2l, the valve 26being securely soldered to casing I at a point 28 to prevent leakage. Inorder that the pressure of the fluid, which may be air, gas, or acompressed liquid, under pressure within the casing, may be accuratelydetermined, a pressure gauge 29 is provided, it having a scale usuallyindicating from Zero to 300 pounds pressure.

The transmitting vacuum tube 33 has cathode leads 34 and 35 located atthe .upper portion of the envelope and a grid lead 35 on the side of theenvelope. The anode 31 is provided with a relatively heavy taperedsleeve 38 which is preferably made of copper. The vacuum tube portion ofcasing I, which is that portion to the right of the dot and dash line 44, is provided with an aperture 39, a base plate 40, clamping stud LlIand knurled thumb nut 42. Securely fastened to rbase plate 4I) is awater inlet and outlet plate 43 which terminates in unions 44 and 45 forcoupling inlet pipe dl and outlet pipe 4S. Plate lili is secured toblock I by suitable screws 4B, block A3 being secured to plate L50 byscrews 49.

Within the aperture 39 in block I there is located a water passagespiral member 50, preferably made of copper, which is of substantiallythe same outside diameter as the inside diameter of aperture 39 andsoldered to block I at point 50A. Around the outside of member 5@ is cuta rectangular helical thread 5I or fluid cooling duct of approximatelythree turns per inch, the depth being about three-eighths of an inch.The spacing between the threads may be about equal to the width of thethread.

If desired, as shown by Fig. 9, aperture 39 may have tapered side walls39A instead of the straight side walls shown by Fig. l. Also, thetapered` sleeve 38A may be provided with an externally located helicalthread EIA to form a fluid cooling duct and positioned in aperture 39Aso as to bein fluid communication with the inlet 4l and outlet 6B.

lThe circulating liquid passage is more clearly indicated by Figs. 8, 8aand 8b which show members I, il() and 4.3, respectively, in perspective.Figs. 8 and 8a are out to show only the fluid cooling duct portion. Theyare additionally cut in section to make the fluid passage more lucid.The arrows pointing upward indicate the inlet ilow of the fluid firstvertically upward land then horizontally along the slot 43a cut toapproximately one half its depth in block 43. Upon entering plate 40,the fluid passes vertically upward through the aperture 40a. and theninto the inlet aperture 52. The lower end of the spiral thread 5l is solocated that the lower end portion of the threaded duct 5D comes in linewith inlet 52. The upper end of threaded duct 50 is arranged to line upwith outlet aperture 53 in block l, the fluid passage then goingvertically down the hole 53a in block l, to plate 40, where it then runshorizontally along slot 53h to aperture 53o to the horizontal slot 53dand then vertically out through outlet pipe 45.

Water may be fed into either pipe 46 or 4l and withdrawn from either 41or 46. Assuming' water is fed into pipe 4l, it flows into the inletaperture 43a at the bottom of the spiral and then spirals around throughthe spiral conduit formed between the aperture 39 and thethreadedmember` to the outlet opening 53 through conduit 53a and out throughpipe 46. Plate 4t may be designed with water passages 43a and 5327reversed to provide for locating tube 33 to the left instead of to theright of the condenser as is shown in Fig. 1.

Anode sleeve 38 is preferably cut with a taper of about two inches perfoot and a corresponding tapered aperture 55 is preferably out in thewater passage member 50. rI"he depth of the tapered aperture 55 isslightly greater than the length of the sleeve 38. The arrangement shownin Figs. 1, 2 and 3 is with the tube located on the right hand side ofFig. 1. However, this arrangement may be reversed by reversing the inletand outlet slots in plate 4U. The central lower portion of sleeve 33 isthreaded with a substantially coarse thread 56 to receive the threadedspindle or stud 4| which is provided with a knurled knob 42 for securelydrawing the tapered contact surface together, so as to provide intimatecontact and reduce all tendency of contact resistance and for ejectingthe tube and tapered block when it is to be removed. This is madepossible by virtue of the fact that a knurled knob 42 is pinned by meansof pin 4l to the stud 4l. The entire outer surface of this device ispreferably heavily plated with silver to reduce the surface resistanceof the high frequency currents.

Fig. 4a shows a single tube and condenser in a circuit employing a splitor balanced input circuit in order to facilitate balancing orneutralization of the capacity coupling between input and outputcircuits. The rectangle 430 includes all of the apparatus shown in Fig.1, the circle 432 corresponding to the tube 33 of Fig. 1. Referencenumeral 430 may also be used to indicate the cooling block 43 of Fig. l,it being noted that the anode 31 is illustrated as being directlyconnected thereto. The grounded plate 434 of the neutralizing condensercorresponds to the wall la of Fig. 1, and the other plate 436 of thecondenser corresponds to the electrode of the neutralizing condenser ofFig. l, including parts Ila, Il, 9, etc. 'Ihe neutralizing connection 22of Fig. 1 is shown on Fig. 4c, as are also the grid connection 35,filament leads 34, 35 and the plate connection 2|. The plate connectionmay be made if desired through metallic inlet pipes 41, 45 which may beground together for bilar conduction of cooling water thereto asdescribed in the patent to H. E. Hallborg, #1,963,131.

Fig. 4U is similar to Fig. 4a, except that it employs a split orbalanced output circuit for facilitating balancing or neutralizing ofcapacity coupling between input and output circuits. In Fig. 4b, it isto be noted that the tube structure 402 is provided with a separateblock 4|() and a separate block 4l2 is provided for the neutralizingcondenser 404, i3, 406. In other Words, block 4|!) includes all of theapparatus to the right of line 4 4 of Fig. 1 and block 4l2 of Fig. 4bincludes all of the apparatus to the left of line 4-4 of Fig. 1.Obviously, the two blocks 4H] and 4t2 cannot be connected together forthat would cause short-circuiting of the output cirsuit. It is believedthat Fig. 4h is self-explanatory in view of the discussion of thepreceding ngures and in View of the legends and the reference numeralsindicated thereon.

Fig. 4c illustrates a wiring diagram of two tube and condenserassemblies in a circuit of which both input and output circuits aresplit or balanced to facilitate balancing or neutralizing of capacitycoupling between input and output circuits. The rectangles 4333 and 433'each contain all of the apparatus shown in Fig. 1, the primed lettersindicating the corresponding corrections or parts which are duplicatedas required by the circuits of Fig. 4c. I prefer in the apparatus shownin Fig. 4c to make the output coil 423 of copper tubes ground togetherand fed' at their midpoints with cooling fluid as described more fullyin the patent to H. E. Hallborg #1,963,131. The ends of the tubes 423are connected to or correspond to the pipes 4E, 4l' of Fig. 1, in theHallborg patent, it being noted that the corresponding points areindicated by reference numerals 34, 35.

Fig. 4d shows a single tube circuit in which both input and outputcircuits are split or balanced, and in which provision is made tobalance or neutralize capacity coupling between input and outputcircuits. Rectangle 433 as described before contains all of theapparatus used in Fig. 1, whereas rectangle 430 has its Vacuum tubereplaced by another variable condenser which may simply be inserted inplace of the tube 33 of Fig. 1, that is to say the tube 33 would beremoved and in its place a structrue such as the neutralizing condenserstructure I3, 2, 5, etc. of Fig. 1 substituted. In this event, one ofthe condenser structures will be cooled but this is not objectionable,or if desired, the cooling inlet and outlet pipes may simply be blockedoff, if cooling of one of the condensers is found undesirable for anyreason.

In practice, I prefer to use the circuit of Fig. 4d for single tubecircuits and that of Fig. 4c for two-tube circuits. These circuits arewell adapted for use in cascaded amplifier and frequency multiplierstages of transmitters. They facilitate balanced couplings from onestage to the next and reduce the tendency for uncontrolled oscillationsto take place due to feedback from one stage to another.

The circuit of Fig. 4d is shown in a somewhat more simplified form inFig. 6 and a mechanical arrangement is given in somewhat more extendedform in Fig. 7.

As before explained, in radio frequency circuits, especially at thehigher frequencies, it is essential that the input circuits be balancedto ground as nearly as possible and the output (plate) circuits shouldalso be balanced. In order to perform this balance in practice, it isessential that there be mechanical symmetry of the circuits. In acircuit where it is desirable to use a single tube for a radio frequencyoscillator or radio frequency amplier circuit, the problem of mechanicalsymmetry becomes a more difficult problem.

It may be noted that one outstanding advantage of the circuit andarrangement of Figs. 6 and '7 is that it is very well adapted to use inransmitters Vwhere some amplifier stages have one tube and some have twotubes.

As Vshown in Fig. '7, compressed air variable condensers in blocks ofthe same size as the tube cooling blocks provide a mechanically andelectrically symmetrical balanced arrangement.

Turning to Fig. 6, which shows a schematic diagram of the arrangementand the position in the circuit of the balancing condensers, capacity C1is a Variable capacitor, and is approximately equal to the grid-platecapacity of tube C2 may be considered the neutralizing capacity andshould be adjustable and Ca is another neutralizing or balancingcondenser which balances the voltage that is impressed across C1. C4 isa small condenser which is approximately equal to the tube grid toground, or grid to cathode, capacity. By using equal size blocks on bothsides, the block capacity to ground of both sides of the plate circuitis balanced.

The layout as shown in Fig. 7, shows compressed air neutralizingcondensers. with diierent mechanical arrangements, types of balancingcondensers other than compressed Y air may be used. The balancingcondenser shown as C4 in Fig. 6 may in some cases not be needed to forma suiciently balanced circuit, or it may be affected by making one ofthe grid leads have a larger capacity to ground than the other, thusaffording the necessary capacity balance without adding a condenser (assuch) to the circuit.

Although the circuit shown in Fig. 6 applies to a single tube ampliilercircuit, it is within the scope of this invention to use more than onetube, on one side (tubes parallel) and by selecting the proper size ofbalancing condensers, have the same balanced symmetry of a single tube.The method used in balancing the ampliiier tub-e as shown in Fig. 6could also be applied to oscillatcr circuits, and condensers C2 and C3would be used to control the regeneration of feedback voltage ratherthan neutralizing condensers.

It is to be noted that the output circuit consists of the two parallellyarranged contacting pipes or tubes im?, '5132, into one oi which throughinlet i3d water is fed and from the other of which through outlet itwater is removed. The pipes lidi?, 'm2 are connected to the pipes di,13S shown more fully in Fig. 1, for the tube block 'idii of Fig. 7.nected to the corresponding pipes or-inlet ports di, dii for thecondenser block lid of Fig. 7. In this case, onev of the condenserswhich replaces the vacuum tube of the tube block 'Mil will be foundwater-cooled, but this is advantageous as maintaining the dimensions ofthe tube blocks substantially alike and thereby maintaining the circuitsymmetrical despite the temperature of the cooling water or fluid used.

The pipe system im), H32 may be tuned by connecting the condenser suchas il 2 thereacross and/or by means of a sliding short-circuitlng straplid.

The doubly grounded cooling fluid system lim, E82 is more fullydescribed and claimed in the Hallborg patent above referred to and thecircuit of Figs. 6 and 7 is described and claimed in the The pipes 76E),IGZ are also conv copending application of Hansell and Goldstine, Ser.No. 191,854, led Feb. 23, 1938.

In the operation of this device ci Fig. 1, as before explained, inletand outlet pipes Il@ and lll are connected to the circulating pump ofthe transmitter and no further opening in the cooling system isnecessary when the tubes are changed, as a spare tube shown in Fig. 5may always be kept on hand which has the standard tapered sleeve 8 sothat when it becomes necessary to replace a tube the change can be madeby merely turning the knurled nut 52, removing tube 33 in its entirety,and placing the spare tube in its place, it being securely clamped bymeans of 'tightening knurled nut i2. Other liquids, iiuids and gases,such as air, hydrogen, oil, prestone, carbon tetrachloride, etc., may bepumped through the system for cooling purposes. In practice, I prefer topass the cooling fluid through the output tuning coil conductoraccording to the invention of I-I. E. Hallborg, U. S. Pat. #1,Q63,131.In other words, I contemplate and envision within the scope of thisinvention the combination of my novel tube and block system as describedherein with any of the circuits shown in the I-Iallborg patent, andconversely contemplate utilizing the cooling system of the I-Iallborgpatent in any of the apparatus herein described. Furthermore, it may befound desirable to use a series of block systems employing onlycondensers rather than a condenser and tube and also to water cool oneor more of the condensers as described herein. This and othercombinations of features are obviously within the scope of my presentinvention which accordingly is not to be considered limited in scope.

So far, I have described the indirectly cooled vacuum tube and iiuidcooled block in arrangements most suitable for high frequency operation.

However, it may be used just as advantageously in low frequencyamplifying or modulating arrangements. The improved cooling, preventionof boiling and prevention of excessive heating of spots on the anode dueto boiling greatly increase the permissible power dissipation at theanode. In class A audio amplifiers, and in modulators used in theI-Ieising modulation system, the limiting anode dissipation usually setsa fundamental limit in the power input and output of each tube. By meansof my improved cooling arrangement, the permissible power dissipationper tube may be greatly increased and this makes possible a greatreduction in the number of ampliers or modulator tubes required. Inradio telephone broadcast transmitters, for example, class B modulatorshave been generally adopted with a consequent loss in quality ofmodulation and ease of operation in order to reduce the number and costof modulator tubes. With tubes of increased power dissipation, accordingto this invention, the number of modulator tubes required for theHeising constant current modulating system may be reduced to aboutone-half or one-third of the number formerly required and the advantagesof the I-Ieising system retained without excessive tube costs. I havenot shown schematic circuit diagrams of low frequency ampliers andmodulators employing the indirectly cooled tubes since these circuitsare so well known as to be obvious to one skilled in the art.

It is to be distinctly understood that this invention is not limited tothe apparatus illustrated but is to be construed broadly.

What is claimed is:

1. In combination, a vacuum tube and a condenser, a metallic blockhaving a tapered aperture, a second aperture forming one electrode ofsaid condenser and located in the saine plane as said tapered aperture,a tapered metallic sleeve fitted within said tapered aperture, saidtapered sleeve having a helical cooling fluid chan nel out on theoutside of said sleeve, a vacuum tube mounted Within an opening in saidsleeve, means for circulating a cooling fluid through said channel, andmeans for clamping said tube Within an opening in said block.

A transmitting device having common electrodes for the anode of atransmitting tube and a condenser comprising a metallic block having acylindrical aperture to receive a cooling duct member for the anode ofysaid tube, a second cylindrical aperture adjacent said iirst apertureacting as one of the electrodes of said condenser, and cooling meansconnecting said duct member in said block with a fluid supply source forcooling both the tube and the condenser.

3. A transmitting device having common electrodes for the anode of atransmitting tube and a condenser comprising a metallic block having acylindrical aperture to receive a cooling duct member for the anode ofsaid tube, a second cylindrical aperture adjacent said first apertureacting as one of the electrodes of said condenser, a second condenserelectrode insulatingly secured to said block, and cooling meansconnecting said duct member in said block with a fluid supply source forcooling both the tube and the condenser.

4. A transmitting device having common electrodes for the anode of atransmitting tube and a condenser comprising a solid metallic blockhaving a cylindrical aperture to receive a cooling duct for the anode ofsaid tube, a second cylindrical aperture located in the same plane withand adjacent said rst aperture acting as one of the electrodes of saidcondenser, cooling means connecting said duct member in said block Witha iiuid supply source for cooling both the tube and the condenser.

5. A combined vacuum tube and compressed air condenser comprising acooling block of substantially heavy metal, a metallic sleeve for atleast one of the electrodes of said tube, said metallic cooling blockhaving liquid cooling means wherein the flow of the liquid enters fromthe bottom of said block and having its outlet in fluid communicationwith the upper portion of said block, said block having a cylindricalaperture for receiving the sleeve of substantially the same periphery asthat of the sleeve of said tube electrode, and a second cylindricalaperture in said block Which acts as an electrode for said condenser.

6. A transmitting device having a common electrical connection for theanode of a transmitting tube and one electrode of a condenser comprisinga metallic block having an aperture to receive the anode of said tube, asecond aperture adjacent said irst aperture acting as one of theelectrodes of said condenser, cooling means in said block for both thetube and the condenser, and clamping means comprising a threaded studand a thumb nut for clamping said tube in intimate contact Within saidblock.

rI. In combination a vacuum tube and condenser comprising a taperedsleeve which surrounds the anode electrode of said tube, a solidmetallic cooling block having an aperture of substantially the sameperiphery as that of said tapered sleeve for said anode electrode, asecond aperture in said block forming one electrode of said condenser,the cross-sectional area of said block being substantially greater thanthe crosssectional area of said aperture, and a uid cooling duct locatedadjacent said first mentioned aperture to provide cooling means for saidanode electrode.

8. In combination a vacuum tube and condenser comprising a taperedsleeve surrounding the anode electrode of said tube, a solid metalliccooling block having an aperture of substantially the same periphery asthat of the tapered sleeve for the tube electrode, a second aperture insaid block forming one electrode of said condenser, and means comprisinga cooling duct cut around theoutside of said sleeve and connected to afluid supply source for circulating cooling fluid through said coolingblock.

9. In combination a vacuum tube and a condenser, a metallic block havinga tapered aperture, a tapered metallic sleeve fitted Within saidaperture, a second aperture in said block forming one electrode of saidcondenser, said tapered sleeve having a cooling fluid channel helicallycut around the outside periphery thereof, said vacuum tube being mountedWithin an opening in said sleeve, and means connecting said fluidcooling channel with an external fluid supply source for circulatingcooling uid through said channel.

10. In combination a vacuum tube and a condenser, a metallic blockhaving a tapered aperture, a tapered metallic sleeve fitted Within saidaperture, a pair of electrodes for said condenser located Within saidmetallic block, said tapered sleeve having a cooling iiuid channelhelically cut around the outside of said sleeve, said vacuum tubemounted Within an opening in said sleeve, and means for connecting saidfluid channel with a iiuid supply source for circulating a cooling fluidthrough said channel.

11. A transmitting device having a common electrical connection for theanode of a transmitting tube and one electrode of a compressed aircondenser comprising a metallic block having an aperture to receive theanode of said tube, a second aperture adjacent said rst aperture actingas one of the electrodes of said condenser, an insulator located oversaid second aperture for supporting the other condenser electrode,cooling means in said block for both the tube and the condenser, andclamping means for clamping said tube in intimate contact Within saidblock.

12. A transmitting device having a common electrical connection for theanode of a transmitting tube and one electrode of a compressed aircondenser comprising a metallic block having an aperture to receive theanode of said tube, a second aperture adjacent said first apertureacting as one of the electrodes of said condenser, an insulator locatedover said second aperture for supporting the other condenser electrode,cooling means in said block for both the tube and the condenser, a platesecured to the lower portion of said metallic block having couplingmeans for coupling a fluid duct which is located adjacent said firstmentioned aperture with a iiuid supply source for cooling the anode ofsaid tube.

CLARENCE W. HANSELL.

